Texas became the first state to require school-age girls to be vaccinated against the sexually transmitted virus, though several states are considering the same move.

HPV, which also causes genital warts, is the most common sexually transmitted disease in the country. Several strains have been linked to cervical cancer, which kills about 3,700 Americans a year.

However, Concerned Women for America (CWA) believes that the vaccine should be optional and up to the parents -- not the government -- to choose whether or not their daughter receives the vaccination.

The group argues that the flu virus kills more than 60,000 people annually in the U.S., and yet the flu vaccine remains optional.

In a statement, the Catholic Medical Association (CMA) said while it encourages the use of the vaccine — Gardasil — which it calls “safe, effective, and ethically acceptable”, it rejects efforts to legislate that girls be vaccinated against HPV. The drug is manufactured by Merck.

“Making school attendance conditional on HPV vaccination does not make sense, because girls who are not vaccinated pose no threat, as they would with communicable diseases such as mumps, measles, and polio, to other children attending school,” said Dr. Paul Cieslak in a statement.

CMA executive director John Brehany said the fact that HPV is spread primarily by sexual contact does not render vaccination against it unethical.

“Healing and preventing diseases, no matter what their source, are acts of mercy and a moral good,” he said.

In addition, Brehany said, overriding objections that parents might have to HPV vaccination is a violation of parental rights. It would be counterproductive to undermine parents’ sense of responsibility for their children in this sensitive area, he added.

The CMA statement insisted that support for the vaccine, and similar vaccines in the future, should not be used to undermine support for efforts to promote chastity and to reduce extramarital sexual activity.